Attempting to reland the Overview Button Change.

ash/system/overview/overview_button_tray.h

Index: ash/system/overview/overview_button_tray.h
diff --git a/ash/system/overview/overview_button_tray.h b/ash/system/overview/overview_button_tray.h
new file mode 100644
index 0000000000000000000000000000000000000000..0a16e4781f99bb90ae337634bc2561e9b498e91b
--- /dev/null
+++ b/ash/system/overview/overview_button_tray.h
@@ -0,0 +1,58 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_SYSTEM_OVERVIEW_OVERVIEW_BUTTON_TRAY_H_
+#define ASH_SYSTEM_OVERVIEW_OVERVIEW_BUTTON_TRAY_H_
+
+#include "ash/ash_export.h"
+#include "ash/shell_observer.h"
+#include "ash/system/tray/tray_background_view.h"
+
+namespace views {
+class ImageView;
+}
+
+namespace ash {
+
+// Status area tray for showing a toggle for Overview Mode. Overview Mode
+// is equivalent to WindowSelectorController being in selection mode.
+// This hosts a ShellObserver that listens for the activation of Maximize Mode
+// This tray will only be visible while in this state. This tray does not
+// provide any bubble view windows.
+class ASH_EXPORT OverviewButtonTray : public internal::TrayBackgroundView,
+                                      public ShellObserver {
+ public:
+  explicit OverviewButtonTray(internal::StatusAreaWidget* status_area_widget);
+  virtual ~OverviewButtonTray();
+
+  // internal::ActionableView:
+  virtual bool PerformAction(const ui::Event& event) OVERRIDE;
+
+  // ShellObserver:
+  virtual void OnMaximizeModeStarted() OVERRIDE;
+  virtual void OnMaximizeModeEnded() OVERRIDE;
+
+  // internal::TrayBackgroundView:
+  virtual bool ClickedOutsideBubble() OVERRIDE;
+  virtual base::string16 GetAccessibleNameForTray() OVERRIDE;
+  virtual void HideBubbleWithView(
+      const views::TrayBubbleView* bubble_view) OVERRIDE;
+  virtual void SetShelfAlignment(ShelfAlignment alignment) OVERRIDE;
+
+ private:
+  friend class OverviewButtonTrayTest;
+
+  // Creates a new border for the icon. The padding is determined based on the
+  // alignment of the shelf.
+  void SetIconBorderForShelfAlignment();
+
+  // Weak pointer, will be parented by TrayContainer for its lifetime.
+  views::ImageView* icon_;
+
+  DISALLOW_COPY_AND_ASSIGN(OverviewButtonTray);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SYSTEM_OVERVIEW_OVERVIEW_BUTTON_TRAY_H_